I don't think so. You have to remember that it was a very bloody age. World War One was followed by the Russian civil war, which was possibly even bloodier (records are uncertain) and by a considerable amounts of violence in Turkey, where the ancient Greek communities were annihilated, the Balkans, Kurdistan, Arabia (the rise of the house of Saud) and Somalia. It may be that the general instability and decline in living standards caused by the war[s] may itself have encouraged the disease. However, this Spanish flu has some miraculous properties: the first mention I came across of it spoke of ten million dead, then a couple of years ago it was twenty, and now you mention forty! How can a disease be so retroactively deadly?